The invention relates to a process for the posttreatment of welded compound panels. The invention also relates to a device for carrying out the process.
Especially for the motor vehicle industry, but also for other applications, sheet-metal blanks (so-called "compound panels" or "tailored blanks") are increasingly being produced which are assembled from a number of flat sheet-metal parts of equal or unequal thickness e.g. by roller seam welding or laser welding. These blanks are formed into structural components, such as car body parts, which possess precisely defined characteristics due to their having portions of dissimilar thickness or material properties. Production of these blanks is extensively mechanized and is performed in large high-capacity production lines comprising automatic welding machines, conveyor systems and storage stations.
After welding, the weld margins are treated with oil to prevent rust and, if need be, are also brush treated. To prevent the oil from vaporizing, or even burning, it is not applied until the welded seam has cooled to a temperature of 100.degree. C. or below. As the sheets are heated to around melting point (in the region of 1500.degree. C.) in the welding process and are still at a temperature of 1000.degree.-1200.degree. C. after leaving the welding rollers, a minimum cooling time of approx. 3 to 5 minutes must be allowed for in the layout of the welding line, that is to say, a buffer line of the requisite length, or even intermediate storage, must be provided between the welding station and the oiling station; the result is extended and complex production lines.
It is therefore the object of the invention to provide a process for the posttreatment of compound panels which does not possess these drawbacks, and which produces treated panels quickly and without taking up a lot of space.
This object is attained by the features of the present invention.